Tulare Lake

Pulse Flows Component of the Water Storage Investment Program Groundwater Projects Supplemental Environmental Impact Report

California Department of Water Resources (DWR) | July 30th, 2024

This final supplemental environmental impact report (Final SEIR) has been prepared for the Pulse Flows Component of the Water Storage Investment Program (WSIP) Groundwate

This final supplemental environmental impact report (Final SEIR) has been prepared for the Pulse Flows Component of the Water Storage Investment Program (WSIP) Groundwater Projects (Pulse Flows Component). The Final SEIR is a supplement to three certified environmental impact reports (EIRs) prepared pursuant to the California Environmental Quality Act (CEQA) for three independent WSIP projects (referred to herein as the “WSIP Groundwater Projects”): (1) the Chino Basin Program, (2) the Kern Fan Groundwater Storage Project (Kern Fan), and (3) the Willow Springs Water Bank Project (Willow Springs).

Quantification of record-breaking subsidence in California’s San Joaquin Valley

Nature Portfolio (Springer Nature) | November 19th, 2024

Quantifying anthropogenic contributions to century-scale groundwater salinity changes, San Joaquin Valley, California, USA

Science of the Total Environment (Elsevier) | June 15th, 2018

Total dissolved solids (TDS) concentrations in groundwater tapped for beneficial uses (drinking water, irrigation, freshwater industrial) have increased on average by abo

Total dissolved solids (TDS) concentrations in groundwater tapped for beneficial uses (drinking water, irrigation, freshwater industrial) have increased on average by about 100 mg/L over the last 100 y ears in the San Joaquin Valley, California (SJV). D uring this period land use in the SJV changed from natural vegetation and dryland agriculture to dominantly irrigated agriculture with growing urban areas. Century-scale salinity trends were evaluated by comparing TDS concentrations and major ion compositions of groundwater from wells sampled in 1910 (Historic) to data from wells sampled in 1993 –2015 (Modern). TDS concentrations in subregions of the SJV, the southern (SSJV), western (WSJV), northeastern (NESJV), and southeastern (SESJV) were calculated using a cell-declustering method. TDS concentrations increased in all regions, with the greatest increases found in the SSJV and SESJV. Evaluation of the Modern data from the NESJV and SESJV found higher TDS concentrations in recently recharged (post-1950) groundwater from shallow (b50 m) wells surrounded predominantly by agricultural land uses, while premodern (pre-1950) groundwater from deeper wells, and recently recharged groundwater from wells surrounded by mainly urban, natural, and mixed land uses had lower TDS concentrations, approaching the TDS concentrations in the Historic groundwater. For the NESJV and SESJV, inverse geochemical modeling with PHREEQC indicated that weathering of primary silicate minerals accounted for the majority o f the increase in TDS concentrations, contributing more than nitrate from fertilizers and sulfate from soil amendments combined. Bicarbonate showed the greatest increase among major ions, resulting from enhanced silicate weathering due to recharge of irrigation water enriched in CO2 during the growing season. The results of this study demonstrate that large anthropogenic changes to the hydrologic regime, like massive development of irrigated agriculture in semi-arid areas like the SJV, can cause large changes in groundwater quality on a regional scale.

Quantifying the Relationship Between Atmospheric River Origin Conditions and Landfall Temperature

American Geophysical Union (AGU) | October 11th, 2022

The temperature of landfalling atmospheric rivers (ARs) has direct implications for regional water resources. Compared to cool ARs, warm ARs can result in more surface ru

The temperature of landfalling atmospheric rivers (ARs) has direct implications for regional water resources. Compared to cool ARs, warm ARs can result in more surface runoff and flooding, less water availability via low snow accumulations and enhanced snowmelt, and greater challenges for storm forecasting and reservoir operations. Based on case studies, ARs with subtropical origin locations and warm origin conditions are assumed to be associated with warmer landfall temperatures—though, to date, this has not yet been demonstrated systematically. We analyze North Pacific ARs that made landfall along the West Coast of North America from 1980 to 2017. We find that ARs originating over the subtropical Pacific Ocean near Hawaii (“Pineapple Express”-type ARs) are indeed 1.5°C warmer and 2 kg/m2 moister in winter than ARs originating elsewhere. We extend this analysis for the full study population of ARs by quantifying AR origin conditions, including the spatial distribution of origin temperature, moisture content, and integrated vapor transport (IVT). We use fixed effects multivariate regression to quantify the relative influence of the origin conditions on landfall temperature. Our regression models show that AR origins with lower latitudes, longer AR lifetimes, and stronger IVT are associated with warmer landfall temperatures and that ARs that start warm generally stay warm. We also find that the phase of the El Niño/Southern Oscillation does not exhibit a consistent relationship with AR landfall temperature. Overall, our results partially affirm—yet also complicate—common assumptions about the role of different origin conditions in landfalling AR temperature.

Rapid decline of California’s native inland fishes: a status assessment

University of California, Davis (UC Davis) | November 1st, 2010

Degradation of freshwater ecosystems is a global crisis best understood through intensive study of well-studied regional faunas. A quantitative protocol was used

Degradation of freshwater ecosystems is a global crisis best understood through intensive study of well-studied regional faunas. A quantitative protocol was used to determine conservation status of all 129 freshwater fishes native to California. Seven (5%) are extinct; 34 (26%) qualified for listing as endangered or threatened species; 32 (25%) were rated as imperiled, qualifying as California Species of Special Concern, with potential for listing; 34 (26%) rated being on a watch list and 22 (17%) were found to be relatively secure. Of 31 species officially listed under federal and state endangered species acts, 17 (55%) clearly qualified for listing under our criteria and 12 (39%) were rated as species of special concern. Conversely, of 34 extant species with the lowest ratings under our criteria, only 17 (50%) were officially listed. Climate change, area occupied and anthropogenic threats had the largest negative impact on status. Of the 15 categories of anthropogenic threats analyzed, those most likely to diminish status were alien species, agriculture and dams. Overall, 83% of California’s freshwater fishes are extinct, endangered, or in decline, a 16% increase since 1995 and a 21% increase since 1989. The decline seen in California’s inland fishes is probably typical of declines in areas that are less well documented, indicating a strong need for better methods of conservation of freshwater ecosystems.

Rapid subsidence over oil fields measured by SAR interferometry: Geophysical Research Letters

American Geophysical Union (AGU) | September 1st, 1998

The Lost Hills and Belridge oilfields are in the San Joaquin Valley, California. The major oil reservoir is high porosity and low permeability diatomite. Extraction of la

The Lost Hills and Belridge oilfields are in the San Joaquin Valley, California. The major oil reservoir is high porosity and low permeability diatomite. Extraction of large volumes from shallow depths causes reduction in pore pressure and subsequent compaction, forming a surface sub- sidence bowl. We measure this subsidence from space using interferometric analysis of SAR (Synthetic Aperture Radar) data collected by the European Space Agency Remote Sensing Satellites (ERS-1 and ERS-2). Maximum subsidence rates are as high as 40 mm in 35 days or > 400 mm/yr, measured from interferograms with time separations ranging from one day to 26 months. The 8- and 26-month inter-ferograms contain areas where the subsidence gradient exceeds the measurement possible with ERS SAR, but shows increased detail in areas of less rapid subsidence. Synoptic mapping of subsidence distribution from satellite data powerfully complements ground-based techniques, permits measurements where access is difficult, and aids identification of underlying causes

Recent and Forecasted Increases in Coccidioidomycosis Incidence Linked to Hydroclimatic Swings, California, USA

U.S. Centers for Disease Control and Prevention (CDC) | March 4th, 2025

Incidence of coccidioidomycosis, an emerging infectious disease caused by Coccidioides spp. fungi, has increased dramatically since 2000. In 2023, California, USA, report

Incidence of coccidioidomycosis, an emerging infectious disease caused by Coccidioides spp. fungi, has increased dramatically since 2000. In 2023, California, USA, reported a near-record 9,054 coccidioidomycosis cases (only surpassed by 9,093 cases in 2019). During April 2023–March 2024, a period capturing the full seasonal rise and fall in incidence, California reported 10,519 cases, 39% higher than the same period the previous year. The 2023 spike in incidence might be attributable, in part, to a swing from extreme drought to heavy precipitation during winter 2022–2023. Transitions from dry to wet years have been linked to increased coccidioidomycosis incidence. Soil moisture during wet winters is hypothesized to support fungal growth, contributing to an abundance of spores available for airborne dispersal during hot, dry conditions characteristic of summer and early fall. Drought preceding rainy seasons might enhance fungal growth by eliminating microbial competitors from soils or by affecting rodent populations, a putative reservoir host and nutrient source for the fungus. During 2020–2022, California experienced severe drought. An unusually wet winter followed in 2022–2023; statewide precipitation exceeded 150% of average, among the top 10 wettest seasons in the past century. Statewide precipitation during the 2023–2024 wet season was 115% of the long-term average, marking the second consecutive wetter-than-average season after a severe drought. That pattern suggested high coccidioidomycosis incidence might continue throughout the 2024 transmission year. We developed a disease forecast to guide public health alerts and messages by pinpointing when and where disease risk is expected to be highest. Such targeted messaging can raise awareness about disease risk, leading to earlier diagnosis and more effective disease management.

Recent California Water Transfers: Implications for Water Management

Natural Resources Journal (University of New Mexico) | January 3rd, 1995

The 1991 and 1992 California Drought Emergency Water Banks were the first large water transfer programs in the nation in which the state served as the predominant broke

The 1991 and 1992 California Drought Emergency Water Banks were the first large water transfer programs in the nation in which the state served as the predominant broker for water trades. Although the state-sponsored Water Banks have drawn widespread attention, there have been a great number of water transfers and exchanges taking place in California independently of the state. These transfers illustrate well the widespread applicability of transfers in managing water resource systems, as well as the multiple mechanisms available for effecting water transfers. This article focuses on California's recent experiences with water transfers, and offers a series of potential lessons for federal, state, and local managers for integrating water transfers in regional water resource systems.

Recent California Water Transfers: Implications for Water Management

Natural Resources Journal (University of New Mexico) | December 1st, 1995

The 1991 and 1992 California Drought Emergency Water Banks were the first large water transfer programs in the nation in which the State served as the predominant

The 1991 and 1992 California Drought Emergency Water Banks were the first large water transfer programs in the nation in which the State served as the predominant broker for water trades. Although the State-sponsored Water Banks have drawn widespread attention, there have been a great number of water transfers and exchanges taking place in California independently of the State. These non-State transfers illustrate well the widespread applicability of transfers in managing water resource systems, as well as the multiple mechanisms available for effecting water transfers. This paper focuses on California's recent experiences with water transfers, and offers a series of potential lessons for federal, state, and local managers for integrating water transfers in regional water resource systems.

Recent decreases in snow water storage in western North America

Nature Portfolio (Springer Nature) | May 22nd, 2023

Mountain snowpacks act as natural water towers, storing winter precipitation until summer months when downstream water demand is greatest. We introduce a Snow Storage Ind

Mountain snowpacks act as natural water towers, storing winter precipitation until summer months when downstream water demand is greatest. We introduce a Snow Storage Index (SSI), representing the temporal phase difference between daily precipitation and surface water inputs—sum of rainfall and snowmelt into terrestrial systems—weighted by relative magnitudes. Different from snow water equivalent or snow fraction, the SSI represents the degree to which the snowpack delays the timing and magnitude of surface water inputs relative to precipitation, a fundamental component of how snow water storage influences the hydrologic cycle. In western North America, annual SSI has decreased (p